Optimization of submerged fermentation conditions for longan vinegar production.

In this research,longan was used as raw material to produce the fruit vinegar.The single-factor tests and the orthogonal tests showed that the results of experiments showed that the optimum alcoholic fermentation conditions in fruit vinegar production were sugar content 20%,fermentation temperature 30 ℃,yeast dosage 8% and initial pH 4.5,while the optimum acetic acid fermentation conditions were temperature 35℃,alcohol content 8%,ventilation volume 1:4,and inoculation size 8%.